I Need a 400V, 3-pole, 25A circuit breaker.....what would you use?

[danielplace]

A 400, a 415, a 480 and a 600 volt breaker will all work.

Think he found a 480 volt for $39 each. Worth a shot could be junk or most likely it will do the job fine for the purpose for quite some time.

Switching it on and off with no/minimum load so it should last.

[Oscar]

Yup, I was 99.999999999999999% sure, thank you for confirming.

[smithdoor]

I would look on Amazon I found China made breakers .
www.aliexpress.com will have your breaker but will take time

Dave

Yup, I was 99.999999999999999% sure, thank you for confirming.

[Oscar]

I would look on Amazon I found China made breakers .
www.aliexpress.com will have your breaker but will take time

Dave

You are way too late to the party.

[Oscar]

WillieB + danielplace: B or C curve ? The welder pulls I1max at 21.5A, which is only a 1.1 factor over a 20A rating, so even with a 20A breaker, the welder would hit overload (duty cycle at 77°F is ~ 45%) before a B-curve breaker would trip?





Thoughts?

[Willie B]

It is my opinion that protecting from duty cycle limits is not the job of the circuit breaker. I don't want to wait for a circuit breaker to trip.
Circuit breaker properly sized will not trip under any normal operating condition.
Internal thermal protection senses heat build up & opens to prevent damage, or more accurately, limit damage.
I still feel it is best to me mindful of heat, and give it a rest to cool after a tough task. In my experience, I'm the fitter. I have plenty to do to let the fan do its job, don't need to abuse the welder.

If that level of control is desired, consider a motor control. Square D is the brand I use. Motor logic controls have magnetic sensing & are adjustable.

[Munkul]

Always choose a C or a D type breaker for a welder. Even inverters. The current inrush can trip a B type, and sometimes an arc-up. I have a B16 on one of my sockets and my welders often trip it on start-up. The others are C20s and have no problems.

The Imax is not the same as instantaneous inrush.

[smithdoor]

The best I found was time delay fuses for welding and machine tools. The breakers I need to increase the size but time delay fuses I could run smaller wires and still meet code.

Dave

Always choose a C or a D type breaker for a welder. Even inverters. The current inrush can trip a B type, and sometimes an arc-up. I have a B16 on one of my sockets and my welders often trip it on start-up. The others are C20s and have no problems.

The Imax is not the same as instantaneous inrush.

[Oldendum]

I have a 3-pole, 480v, 100A Westinghouse breaker here that is about 1/3 the size of a shoebox. Came out of the community college welding shop when they did a complete renovation. Probably a spare.

[Oscar]

I have a 3-pole, 480v, 100A Westinghouse breaker here that is about 1/3 the size of a shoebox. Came out of the community college welding shop when they did a complete renovation. Probably a spare.

Nice, but doesn't help me, lol.

WillieB, thanks but you mis-understood what I was getting at.

Munkul, thanks for the insight.

[Insaneride]

Nice, but doesn't help me, lol.

WillieB, thanks but you mis-understood what I was getting at.

Munkul, thanks for the insight.

Why even ask for help???

Edit: why ask for help?

[smithdoor]

I agree 👍

Dave

Why even ask for help???

Edit: why ask for help?

[Oscar]

because some people do get me, and don't get side tracked and do post great replies. 100A is pretty outside the range of what I need, dont'cha say?

[Woznme]

I get you. Lone Star beer and ribs. Who doesn't get that?

[SweetMK]

I am wondering why fuses are not the answer to this question??
In the 1990s, where I worked, we built a LOT of high voltage controls for large motors,,

Everything was fuse protected, not circuit breakers.
With fuses, it is real easy to customize for an exact amperage, and you can select the "rate" at which the protection occurs.

This was multi-million dollar drives we were manufacturing,,
(We even built the drives that were involved in the "little problem" that occurred in Japan at the nuclear power plant a few years ago)

[Oscar]

I get you. Lone Star beer and ribs. Who doesn't get that?

and Brisket!

I am wondering why fuses are not the answer to this question??

Well, is there not more than 1 way to skin a cat? I'm certain they would work, but they are not the only way.

[SlowBlues]

the brisket looks delicious, but did you notice the demon eyes peering down from on high? Looks like the punisher has his eyes on your meat.

[Oscar]

the brisket looks delicious, but did you notice the demon eyes peering down from on high? Looks like the punisher has his eyes on your meat.

hehe, yup looks pretty cool. Slow n low, 220-230F for ~24 hours on blackjack oak. Fall apart tender.

[Insaneride]

because some people do get me, and don't get side tracked and do post great replies. 100A is pretty outside the range of what I need, dont'cha say?

100A is outa the range of what you need but you don't need to weld, don'tcha say?

Seriously tho, you get a machine that wasn't engineered for your mains, you want to re-invent electrical panel, diss all advice and then your never gonna weld anything of significance with it. No?

My advice altho you won't except is; use fuse

[Oscar]

No I don't diss all the advice. I'm actually taking some advice here and there from people who's opinion/expertise I do hold in high regard. If you don't like what I do, then too bad. It doesn't affect your life, at least it shouldn't, so why would it matter what I do or don't do with my crap? Your "serious" question is completely irrelevant.

[smithdoor]

I still post as it will help others.
Oscar is trying excuse him self.
Some need the information as they only read post.

Dave

Why even ask for help???

Edit: why ask for help?

[Oscar]

I still post as it will help others.
Oscar is trying excuse him self.
Some need the information as they only read post.

Dave

You are the last person here who would know what I am doing. Please don't say what I am doing or not doing. I am certainly not trying to excuse myself from this thread.

[smithdoor]

I guess I missed what you are saying.

Sorry 😞

You are the last person here who would know what I am doing. Please don't say what I am doing or not doing. I am certainly not trying to excuse myself from this thread.

[M J D]

The output on a typical rotary phase converter as provided doesn't have overload protection on the output side. My understanding is( it can be hard to tell with Oscar) is that he wants to protect the output side on the converter before it feeds the step up transformer. I did similar with mine, minus the transformer. I used the 400 or 480 volt rated ones from Amazon mentioned in a previous post. I used dinse rail mount types mounted inside the enclosure.

[Oscar]

The output of the RPC is already protected by a standard 240V/40A 3-pole breaker. I was looking for ideas/suggestions on actual breakers (and only breakers) that are rated to 400V (or even higher) for the output of the transformer. There is nothing to "tell", as I'm always pretty direct with my inquiries. I was looking for suggestions on suitable 400V 3-ph breakers, nothing more, nothing less.